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Re: MIME implementation documentation

1996-08-17 18:52:33
When in doubt, write a Web page....

I have written up a Web page for the Last Call on

http://domen.uninett.no/apps/last-call/mime-draft2.html

and attached a text version to this document.
Given the debate that has occured, I regard the question of 
multipart/alternative as settled, while there is still missing evidence for 
multipart/parallel, generation of nested body parts and handling of external 
body parts.

When new evidence arrives (on this list, please!), I will update the Web page.

            Harald T. Alvestrand
            Apps AD


               LAST CALL FOR MIME DOCUMENTS TO RECYCLE AT DRAFT
                                       
   The following Last Call has been issued:

The IESG has received a request to consider the following Protocol
Actions:


1. Multipurpose Internet Mail Extensions (MIME) Part One:  Format of
   Internet Message Bodies"  for the
   status of Draft Standard.

2. Multipurpose Internet Mail Extensions (MIME) Part Two:  Media Types
    for the status of Draft
   Standard.

3. MIME (Multipurpose Internet Mail Extensions) Part Three: Message
   Header Extensions for Non-ASCII Text
    for the
   status of Best Current Practice.

5. Multipurpose Internet Mail Extensions (MIME) Part Five:  Conformance
   Criteria and Examples  for the
   status of Draft Standard



The IESG plans to make a decision in the next few weeks, and solicits
final comments on this action.  Please send any comments to the
iesg(_at_)ietf(_dot_)org or ietf(_at_)ietf(_dot_)org mailing lists by August 8, 
1996.

   No objections to the Last Call were received before August 8.
   
   After the timeout date for the Last Call comments, the following
   issues with regard to implementation experience have been raised:
     * Is multipart/alternative widely implemented for generation?
     * Is multipart/alternative widely implemented for reception?
     * Is multipart/parallel widely implemented?
     * Are Nested Body Parts widely implemented?
     * Are External Body Parts widely implemented?
       
   The issue here is if the "two implementations" rule (which
   traditionally have allowed two experimental implementations without
   terribly useful user interfaces) should be strengthened for a
   specification of this maturity to mean "two interworking, commercial
   implementations that can be used by someone not terribly skilled in
   the arcana of MIME".
   
   The sections below will give the arguments and evidence in each case.
   
Is multipart/alternative widely implemented for generation?

   The question is if there exist MUAs that can generate a MIME
   multipart/alternative without excessive thinking on the part of the
   user.
   
   The following MIME UAs have been claimed to do so:
     * Cyberdog for the Macintosh
     * Ishmail
     * An yet-unnamed product from Microsoft
       
   This AD regards the question as settled.
   
Is multipart/alternative widely implemented for reception?

   The question is if there exist UAs that display the "best" body part
   (that being defined as the last part of the multipart/alternative that
   the UA is able to display).
   The following UAs have been claimed to do so:
     * Pine
     * Metamail
     * Mac Eudora 3.0
       
   This AD regards the question as settled.
   
Is multipart/parallel widely implemented?

   The question is if there are UAs that display all parts of the
   multipart/parallel "at the same time", as described in the drafts, and
   do not jsut treat it like multipart/mixed, and if there are generating
   UAs.
   
   To date, no generating UA has been identified.
   
   To date, only Metamail has been mentioned as an example of a
   displayer.
   
Are Nested Body Parts widely implemented?

   Many MUAs work according to the "one message with attachments"
   metaphor, which is not the same as the MIME "bodyparts may nest to any
   level" structure. Forwarded messages are not part of this question.
   
   One may argue that the "inline/attachment" distinction that is carried
   in content-disposition is missing functionality in MIME. However,
   content-disposition is the subject of another ongoing action, and will
   have to catch up later.
   
   The question is if there exist MUAs that:
    1. Generate nested multiparts through a reasonable user interface
    2. Usefully display nested multiparts
       
   The following MUAs have reasonable support for generating nested
   multiparts:
     *
       
   The following MUAs have reasonable support for displaying nested
   multiparts:
     * EXMH 1.6.7
       
Are External Body Parts widely implemented?

   The question is if there exist MUAs that:
    1. Generate External Body Parts through a reasonable user interface
    2. Usefully handle External Body Parts
       
   The IETF internet-drafts announcement uses multipart/alternative with
   external body parts to list the ways in which one can get the I-Ds.
   This is special purpose code, and only proves that such messages can
   be generated.
   
   The following MUAs have reasonable support for generating External
   Body Parts:
     *
       
   The following MUAs have reasonable support for handling External Body
   Parts:
     * MH 6.8.3
       
   
     _________________________________________________________________
   
    Harald(_dot_)T(_dot_)Alvestrand(_at_)uninett(_dot_)no
    
   Last modified: Sat Aug 17 09:32:26 1996